The plural of frenulum is frenula.

The "frenulum" of tongue or tongue web (also "lingual frenulum" or "frenulum linguæ")

Yes, a frenulum will not interfere with ejaculation.

A frenum is a male genital piercing. Basically a frenum piercing is a form of a frenulum piercing. So is a fourchette.But really a frenulum piercing is an oral piercing. Frenulum can be either an upper frenulum(smiley), lower frenulum (frowney), or even a tongue web piercing. A frenulum is a fold/piece of tissue that restricts the movement of an organ.

The lingual frenulum. This is the thin bit of skin (technically it is a fold of mucosa) which you can see when you lift up your tongue